The present invention relates to non-volatile memory devices and, more particularly, to a data read method and a program verify method of the non-volatile memory device, in which the influence of coupling is not exerted between bit lines.
A conventional non-volatile memory device employs a method of performing a program operation and a program verify operation on even bit lines and odd bit lines through one sense node, which means each bit line has to be programmed and verified one at a time.
Furthermore, in the sensing period of the read or verify process, the bit line is generally kept floating. In the case where a word line including a programmed cell and an erased cell in two neighboring bit lines is selected, the two bit lines influence each other by coupling capacitance. Thus, a different value from the stored data can be output as a result of the read operation. Furthermore, as a multi-level cell technique for storing several bits in one cell has recently been applied, the states represented by one cell are increased. Accordingly, the distance between threshold voltages, which divides the states of a cell, is significantly reduced. Thus, there is a high possibility that malfunction may occur because of coupling between bit lines.